1,721,083 research outputs found
Emerging technologies for the recovery of rare earth elements (REEs) from the end-of-life electronic wastes: a review on progress, challenges, and perspectives
No full textThe demand for rare earth elements (REEs) has significantly increased due to their indispensable uses in integrated circuits of modern technology. However, due to the extensive use of high-tech applications in our daily life and the depletion of their primary ores, REE's recovery from secondary sources is today needed. REEs have now attracted attention to policymakers and scientists to develop novel recovery technologies for materials' supply sustainability. This paper summarizes the recent progress for the recovery of REEs using various emerging technologies such as bioleaching, biosorption, cryo-milling, electrochemical processes and nanomaterials, siderophores, hydrometallurgy, pyrometallurgy, and supercritical CO2. The challenges facing this recovery are discussed comprehensively and some possible improvements are presented. This work also highlights the economic and engineering aspects of the recovery of REE from waste electrical and electronic equipment (WEEE). Finally, this review suggests that greener and low chemical consuming technologies, such as siderophores and electrochemical processes, are promising for the recovery of REEs present in small quantities. These technologies present also a potential for large-scale application.LT
Uniform TiO2/In2O3 surface films effective in bacterial inactivation under visible light
Full text linkThis study shows that the surface modification of TiO2 is an effective route to increase the TiO2 absorption in the visible region up to similar to 600 nm for photocatalytic applications. The In2O3 decorated TiO2 films on polyester obtained by reactive sputtering were shown to accelerate the Escherichia coli inactivation under actinic and simulated solar light. TiO2 sputtered films for 10 min inactivated bacteria within 300 min under actinic light. The inactivation time was reduced when using a TiO2 10 min-In2O3 10 s sample to 150 min when using actinic light and 90 min by simulated sunlight with 50 mW/cm(2) (one half of AM1). Thinner TiO2-In2O3 coatings led to faster bacterial inactivation compared to thicker TiO2-In2O3 layers due to the reverse diffusion of the generated charges. The increase in the optical absorption of the green coloured TiO2-In2O3 film was a function of the In2O3 loading as detected by diffuse reflectance spectroscopy (DRS). Evidence of the lack of TiO2 lattice doping by the sputtered In2O3 was found by X-ray diffraction spectroscopy (XRD). The deconvolution of TiO2 bands detected by X-ray photoelectron spectroscopy (XPS) revealed the existence of Ti4+/Ti3+ signals suggesting redox catalysis at the surface of the TiO2-In2O3. The photo-induced interfacial charge transfer (IFCT) between TiO2 and In2O3 can be accounted for by the band position potentials of both semiconductors. The faster kinetics of TiO2-In2O3 inducing E. coli inactivation with a higher quantum efficiency compared to TiO2 takes place in spite of the low intensity of the IFCT optical absorption bands >400 nm.GPA
Advances in Antimicrobial Coatings
Full text linkThis book is motivated by our passion to compile recent research on antimicrobial surfaces. We aimed to assemble research papers on the preparation of new materials, antimicrobial testing using different pathogens (bacteria, fungi, and viruses), and the relationship between the coating nanostructure and its reactivity towards the studied pathogen(s). We believe that a good antimicrobial coating should by characterized by (i) a fast activity towards the pathogen, (ii) sustainable activity based on the stability of the coating, and (iii) the lowest possible toxicity for humans and reduced risks for the environment. Striking a compromise between these different challenges is difficult and requires more research
Advances in Antimicrobial Coatings
No full textThis book is motivated by our passion to compile recent research on antimicrobial surfaces. We aimed to assemble research papers on the preparation of new materials, antimicrobial testing using different pathogens (bacteria, fungi, and viruses), and the relationship between the coating nanostructure and its reactivity towards the studied pathogen(s). We believe that a good antimicrobial coating should by characterized by (i) a fast activity towards the pathogen, (ii) sustainable activity based on the stability of the coating, and (iii) the lowest possible toxicity for humans and reduced risks for the environment. Striking a compromise between these different challenges is difficult and requires more research
Effect of sol-gel and sputtered TiO2 / iron oxide thin films on E.coli inactivation
No full textSCGCGR-53 970; EPFL - SB - SCGC. Consultable sur demande à la Bibliothèque de l'EPFL / Offered in consultation at the EPFL library
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Thin films for Healthcare Acquired Infections (HAIs) prevention : materials preparation, testing and characterization
Full text linkThis thesis addresses the preparation of antibacterial surfaces for hospital facilities taking biomedical thin polymer films, textiles and catheter as probes. Magnetron sputtering is used to apply the coatings leading to fast bacterial inactivation in the dark and under low intensity light on the selected substrates. These coating are designed and prepared to achieve fast bacterial inactivation to avoid biofilm formation on textiles and polymer films and later on the catheter surface. The infection due to catheters is one of the major problem leading to catheter associated infections (CAIs). The design, preparation, testing and the characterization of the surface properties of uniform and adhesive TiO2,TiO2/Cu, Ag, Cu-films presenting fast bacterial inactivation kinetics on textiles and catheters by up to date HIPIMS and DCMS/DCPMS has been addressed very sparsely until now mainly on 3D objects. No evidence for Ag-Cu coating applied by sputtering covering uniformly the entire catheter surface has been reported up to this date. A modification of the sputtering unit was carried out to coat 3D objects and is one of the main novelties reported in this thesis. The antimicrobial activity was tested on antibiotic resistant bacteria Methycillin resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) alone or jointly representing an important focus of infection by themselves or in the form of pathogenic biofilms in hospital facilities. The bacterial inactivation kinetics was investigated in details under low intensity light and in the dark. The active part of the catheter remains under the patient skin (in the dark). Ag/Cu-has been selected since fast bacterial inactivation proceeds in with a quasi-instantaneous kinetics inducing a cytotoxicity below the limit authorized by the sanitary regulations for mammalian cells. These coatings are also well tolerated by osteoblasts. The sputtered films leading to fast bacterial inactivation and showing low cytotoxicity consisted mainly of TiO2, Cu-TiO2, and Ag/Cu films on 2D surfaces and on catheters with 3D-geometry. This is the first report for materials of this kind, their evaluation and surface properties
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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